1. Field of the Invention
The present invention relates generally to disk drives, and in particular to a disk drive including a head stack assembly with a flex cable guiding support and method of making the same.
2. Description of the Prior Art
The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The head disk assembly includes at least one magnetic disk, a spindle motor for rotating the disk, and a head stack assembly (HSA). The spindle motor includes a spindle motor hub that is rotatably attached to the disk drive base and supports a lowermost one of the disks. The head stack assembly has an actuator assembly having at least one air bearing slider, typically several, for reading and writing data from and to the disk. Each slider includes a transducer head for reading and writing data. The printed circuit board assembly includes a servo control system in the form of a disk controller for generating servo control signals. The head stack assembly is controllably positioned in response to generated servo control signals from the disk controller. In so doing, the attached sliders are controllably moved relative to tracks disposed upon the disk for reading and writing operations.
The head stack assembly includes an actuator assembly, at least one head gimbal assembly, and a flex circuit assembly. A conventional “rotary” or “swing-type” actuator assembly typically includes an actuator having an actuator body. The actuator body is configured to rotate on a pivot assembly between limited positions about an axis of rotation. One or more actuator arms extend from one opposite side of the actuator body. A head gimbal assembly is distally attached to each of the actuator arms. A head gimbal assembly includes an air bearing slider that is attached to a suspension with a gimbal. The suspension resiliently supports the air bearing slider above the tracks of the disk during operation of the disk drive facilitating the slider to “fly” above the disk.
A coil is supported by a coil support that extends from an opposite side of the actuator body. The coil is configured to interact with one or more permanent magnets to form a voice coil motor. The coil is disposed in electrical communication with the disk controller through a flex circuit assembly. Controlled movement of the head stack assembly is achieved by selectively energizing the coil with the generated servo control signals.
The flex circuit assembly is configured (1) to supply current to the actuator coil and (2) to carry signals between the transducer heads and the printed circuit board assembly. The flex circuit assembly includes a flex cable (also referred to as a flex circuit cable or flex circuit), an integrated circuit device, and a cable connector.
At one end of the flex cable there is provided a mounting portion which is attached to the actuator body. Adjacent to the mounting portion, the flex cable contains a terminal pad portion for connecting a plurality of electrically conductive traces embedded within the flex cable to electrical connectors, such as insulated wires. The wires extend along each actuator arm to each transducer head for transmitting data signals to and from the transducer heads. At an opposing end of the flex cable, there is provided a cable connector that is attached to the disk drive base and electrically connected to the printed circuit board assembly.
The flex cable typically includes a base film, a plurality of electrically conductive traces and a cover film. The base film is commonly formed of a polyimide material. The electrically conductive traces are formed upon the base film. The cover film is then selectively disposed over the metal traces and the base film for electrically insulating the traces. Adjacent to the mounting portion of the flex cable, the integrated circuit device is supported by the base film and is electrically connected to the traces. The integrated circuit device includes a preamplifier for enhancing signals passed from the transducer heads.
The flex cable includes a dynamic loop portion that is supported by a cable guide. The cable guide conventionally takes the form of a plastic clip attached to the actuator body. The cable guide maintains the dynamic loop portion in an upright position in planes parallel to the axis of rotation. This configuration permits relatively free rotation of the overall head stack assembly.
As can be appreciated, a reduction in the complexity of manufacturability and assembly with respect to head stack assembly would represent an improved head stack assembly configuration in comparison to the prior art.